Adolescence is defined as the transition from childhood to adulthood and encompasses the broad developmental tasks of establishing a unique identity and developing one’s own autonomy and independence. Brain development also undergoes unique changes during adolescence that can explain many behaviors specific to this developmental period.

Brain development continues well into the 20’s and the last area to develop is the prefrontal cortex, responsible for higher cognitive and emotional functioning. Prefrontal cortex development is largely influenced by experience and this allows us to directly impact adolescent brain development.

After a preadolescent cellular growth spurt in the brain, a pruning process begins in adolescence. The adolescent loses approximately three percent of gray matter in the prefrontal lobes. This pruning works on a “use it or lose it” principle so it is important to repeatedly expose young people to the skills and knowledge needed to become successful adults. Repeated use and exposure will strengthen the neural connections that support these skills so they are not lost during the pruning process.

The speed and efficiency of neural communication is determined by neural sensitivity known as long-term potentiation. Under normal situations, long-term potentiation is highest during adolescence. However, adolescents face many factors that can inhibit long-term potentiation. Things like alcohol and substance use, chronic stress, sleep deprivation, and stimulants interfere with long-term potentiation and slow neural communication. We can help teens minimize exposure to these risk factors through education.

Due to the pattern of brain development, teenagers have greater difficulty reading the emotions of others, a function of the prefrontal lobes, and experience emotions at greater intensity than adults due to a reactive limbic system. We can help develop the neural pathways between the limbic center and prefrontal lobes by helping teens examine and identify emotions (their own and of others) and helping them learn to “put a brake” on their emotions and stop and think before reacting. Activities such as “emotion charades” allows teens the opportunity to both recognize and express emotions.

Research now demonstrates a significant link between exercise and brain functioning and development. Exercise increases blood flow and oxygen level in the brain and this is necessary for optimal cellular growth and function. Exercise also impacts neurotransmitter levels in the brain that can serve to help teens better regulate emotional control.

Knowledge is power and teens should be educated about how the choices that they make during adolescence can have lifelong impacts.

This blog is the final post in a three-part series on adolescent brain development. Click on the links below to read parts one and two:

What determines the individual responses in times of crisis? Why do some freeze and become incapable of responding while others seem to thrive and rise to the challenge in the face of threat? We can look to genetics and a person’s upbringing to determine the neural pathways established in the brain that dictate the varied ranges of response to crises.

In the center of the brain and seated in the limbic system lies a small structure known as the amygdala. The amygdala houses fearful or threatening memories and uses this information to access incoming information to determine potential threats and initiate the “fight or flight” response required to deal with those threats. While information from the amygdala can be sent to the prefrontal lobe for higher cognitive and emotional assessment, it is important to understand that the amygdala is designed to respond immediately to ensure survival.

Genetics will determine the initial sensitivity and response rate of the amygdala. Some individuals are prone to quick emotional responses due to the innate sensitivity of amygdala responsiveness influenced by levels of neurotransmitters and cellular structure. Early upbringing can either enhance or moderate this heightened sensitivity.

Early environment is crucial to the cellular development and connectivity of the amygdala because newborns enter the world unable to regulate their emotional responses. When responsive caregivers immediately respond to meet the needs of their newborn, they help establish neural pathways in the brain that allow the infant to begin to self-regulate and self-sooth in times of distress. Infants who have caregivers that are unresponsive lack the opportunity to establish these pathways for self-regulation. When caregivers are abusive, infants miss opportunities to self-regulate and the initial responsiveness of the amygdala is increased to respond to the threat. Neglectful and abusive environments heighten emotional responses and reactivity and all new information is processed against those threatening memories. An overactive amygdala results in increased anxiety, fear, distrust and mood disorders.

These early patterns generally persist throughout life. While intervention can help moderate the emotional response and change behavioral patterns, in times of crises or in unfamiliar situations we tend to revert to earlier patterns. Certain environmental features or characteristics and mannerisms of others can trigger old fearful memories and initiate the crisis response. Understanding how a person’s stress response was established can help predict their future behavior in crisis situations.

The human brain is a beautiful thing. Nothing matches a healthy brain in efficient, creative, and effective functioning. Normal brain development follows predictable patterns mirroring the mastery of developmental skills at different stages of life. It is important to understand, however, that brain development is strongly influenced by environment. An enriched, supportive environment facilitates healthy brain development; a deprived, harmful, or stressful environment greatly inhibits normal brain development.

There are two developmental periods during which brain growth and development is unparalleled: birth – toddlerhood and pre-adolescence. During both of these stages, there is a tremendous increase in brain matter, particularly in neural connections, or synapses, that allow the brain cells to communicate. This overabundance of brain matter is necessary to accommodate the significant learning that occurs during these periods.

Also common to both periods of brain development is the process called pruning. Neural pruning rids the brain of unused synapses to promote more efficient processing. Again, pruning is highly dependent upon the environment and individual experiences. Exposure to new skills and learning opportunities is crucial during these times.

There are also differences in the brain development of infancy / toddlerhood and adolescence and these differences reflect the developmental tasks that are key to each stage. Much of brain development in the earlier years is inhibitory; neural communication in the brain blocks brain activity in certain areas as the child learns to control their own bodies, emotions, and actions. Brain growth in adolescence is excitatory; this is particularly true for the limbic system, the area of the brain integral to learning, reward, and emotions.

Key to understanding much of adolescent behavior is the knowledge that the limbic system develops and is “primed to respond” much sooner than the prefrontal cortex, the area controlling higher cognitive processes and higher emotional control. Due to this uneven growth pattern, adolescents experience heightened emotions, have more difficulty reading emotions and controlling their own emotions, and engage in thrill-seeking behavior at much greater extent than adults.

Because development of the prefrontal cortex is reliant upon experience, adults can create environments to facilitate this development. Learning opportunities, positive role modeling, adequate rest, diet, and exercise, effective coping skills and reduced exposure to risks factors such as alcohol, drugs, and stress, are all key components to healthy brain development. It is within our power to create experiences for youth that will allow them to maximize the most powerful tool at their disposal, the human brain.

This blog post is the first in a three-part series on brain development. Stay tuned for the next two blog posts on brain development!